Essendon Bombers chairman David Evans fights to keep the club together while the ASADA investigation rolls on.

Getty Images: Scott Barbour

Amid ongoing investigations into Essendon's supplements program and possible doping at the AFL club, questions have arisen over whether the club was tipped off that it was under investigation before the Bombers went public in February this year.

On Thursday, Essendon coach James Hird told reporters he had been present at the home of club chairman David Evans the night before the investigation was announced when a call came from AFL chief Andrew Demetriou.

Hird said he was aware of the contents of the phone call and had told what he knew to Australian Sports Anti-Doping Authority (ASADA) investigators.

On Thursday, January 31, AFL chief executive Andrew Demetriou was briefed by the Australian Crime Commission about its investigation into drugs in Australian sport ahead of the release of the report.

The following Monday, February 4, in response to inquiries from the media about supplement use at Essendon, Evans contacted Demetriou to see if he knew anything about a doping investigation.

On February 5, Essendon officials met the AFL, then later called a press conference at which Evans said the club had gone to the league to request an investigation after receiving information that supplements used by the club may not have been within ASADA guidelines. Essendon promised to co-operate with the AFL and ASADA, with Evans denying that the club had administered performance-enhancing drugs to players.

On February 7, two days after the press conference, the ACC released its report "Organised Crime and Drugs in Sport" into the commission's year-long investigation into Australian sport, which said that organised criminal networks had been involved in distributing drugs to athletes and support staff, including doctors and coaches.

Since early February, Essendon has continued to say publicly that the club is confident its players did nothing illegal.

On February 27, the Bombers announced an independent review into the club's governance of the supplements program, headed by former Telstra boss, Ziggy Switkowski.

The review later handed down a report which painted "a disturbing picture of a pharmacologically experimental environment never adequately controlled or challenged or documented within the club in the period under review."

On May 23, 2013, Essendon chief executive Ian Robson resigned.

Last month, Essendon captain and last year's Brownlow Medal winner Jobe Watson stated in a television interview that he had been given what he believed was AOD-9604, an anti-obesity peptide which is prohibited under section S.0 of the World Anti-Doping Agency (WADA) code, although not on the so-called "banned list".